Die.



Nu. s77,|2:. Patented lune 25, mm.

.1. DONOVAN.

(Application filed May 21, 1900) (No Model.)

Ina 677170 r M y I (##yw.

UNITED STATES PATENT OFFICE.

JAMES DONOVAN, OF THREE RIVERS, MICHIGAN.

DIE.

SPECIFICATION formingpart of Letters Patent No. 677,121, dated June 25,1901. Application filed May 21, 1900. Serial No. 17,450. (No model.)

To aZZ whom it may concern.-

Be it known that I, JAMES DONOVAN, a citizen of the United States,residing at Three Rivers, in the county of St. Joseph and State ofMichigan, have invented certain new and useful Improvements in Dies, ofwhich the following is a specification, reference being had therein tothe accompanying drawings.

The invention relates to dies for forming sheet metal, and moreparticularly to those used for forming cylindrical bodies.

It is the object of the invention to obtain a construction in which themale die will antomatically relieve itself, so that it can be readilywithdrawn from the formed cylinder. The invention consists in theconstruction hereinafter described and claimed.

In the drawings, Figurel is a longitudinal section through the male andfemale dies, and Fig. 2 is a bottom plan view of the male die.

In the formation of cylindrical bodies by dies from heated metallicplates difiiculty is experienced in withdrawing the male die from thework. This is for the reason that the contraction of the sheet metal dueto its cooling in contact with the metal of the die will so firmly clampit to said die as to be nearly impossible to remove it. In theconstruction shown in the drawings this objection is overcome by formingthe male die of a plurality of segments, comprising a central section Aof wedge shape cross-section and side sections 13 and 0 bearing againstsaid wedge and having complementary inclined faces. The central sectionA is preferably formed integral with the head D, which may be secured tothe reciprocating plunger of the press. sections B and O are suspendedfrom this head, preferably by means of the bolts E, which pass throughslotted apertures F in said head. At their upper ends these bolts areprovided with heads or flanges G, adapted to engage with the lower faceof a recess H,

formed in the head D. The bolts are of suffi cient length to permit thesections B and O to drop away from the head D when the heads G of saidbolts are resting on the bottom of the recess.

With the construction described the sections B and 0 will normally hangin a position which permits of their approaching each The other, so asto reduce the diameter of the die from its working size. As soon,however, as the descent of the plunger presses the lower face of thesections B and 0 against the work, which latter is arranged above thefemale die, said sections will be forced upward, causing the centralwedge A to spread them until the die assumes its maximum diameter. Inthe return stroke of the plunger the sections B and C will be first heldfrom movement by the clamping of the work thereon; but the centralwedge-shaped section A is free to be withdrawn, and this will relievethe side pres* sure upon the sections 13 and C and permit them to beWithdrawn.

Although a die has been shown and described which is intended especiallyfor the formation of cylindrical bodies, it is not desired to limit theinvention to this precise construction, as it is evident that such a diemight be employed to equal advantage for forming square or polygonalbodies having parallel sides.

What I claim as my invention is- 1. A male die comprising a plurality ofsec tions having a wedge engagement with each other, said sections beingadapted to form, when operating upon the work, complementary portions ofa continuous surface, and to automatically collapse in withdrawing.

2. The combination with afemale die, of a complementary collapsible maledie, compris ing a reciprocating head, fixed and movable die-sectionscarried thereby forming complementary portions of a continuous externalforming-surface and having oppositely-inclined abutting surfaces,saidmovable section being adapted to be held to its seat by the pressure ofthe work while operating thereon, and to drop away from said seat toreduce the diameter of said die when said head is withdrawn.

3. The combination with a cylindrical female die, of a complementarycylindricalinale die comprisingahead, acentral wedge-shaped sectionfixed thereto, sections upon opposite sides of said central sectionforming complementary portions of a continuous external forming-surfaceand means for attaching said side sections to said head permitting of alimited longitudinal movement upon said wedgeshaped section whereby thediameter of the die is contracted upon the withdrawal'of the head. 7

4. The combination with a cylindrical female die, of a complementarycylindrical male die comprising a head, a central wedge-shapeddie-segment fixed thereto, segments upon opposite sides of said centralsegment forming complementary portions of a continuous externalforming-surface, and headed bolts for loosely suspending said sidesegments from gin presenceof two witnesses.

the head engaging slotted hearings in the lat,- ter and having a limitedlongitudinalwmove; ment thereon for the purpose described.

5. A male die comprising a head, a wedgeshaped central section dependingtherefrom,

section and fiat upper surfaces for hearing vagainst said head, saidcentral and side sections forming complementary portions of an externalcontinuous cylindrical forming-surface, and connections between saidside sections and head permitting of a limited longi- Etudinal andlateral movement in relation thereto.

l'ntestimony whereof I affix my signature JAMES DONOVAN. Vitnesses:

JAMES WHITTEMORE,

M. B. ODOGHERTY.

